The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Passive inflatable restraint systems are often used in a variety of applications, such as in motor vehicles. When a vehicle decelerates due to a collision, an inflatable restraint system deploys an airbag cushion to prevent contact between the occupant and the vehicle, thus minimizing occupant injuries. Such devices usually employ an inflator that can include a pyrotechnic gas generant. The gas generants burn very rapidly to generate heated gas that inflates an airbag. The inflatable device generally requires a sustained gas pressure in the airbag (generally over 5-10 pounds per square inch for at least 40 to 150 milliseconds) to restrain the occupant relative to the vehicle. Thus, gas generants provide gases that fulfill these requirements.
Sometimes, vehicle occupants are not in a predetermined position to receive the benefits of airbag deployment. If the rate of pressure increase in the airbag is too rapid and the amount of pressure generated by the gas generant is excessive, then an out-of-position occupant may not receive the desired benefits of the airbag.
Improvements in gas generant performance remain desirable. Tailoring the performance of the gas generant in an inflatable device system, such as an airbag, can require a complex design of not only the gas generant, but also hardware systems that control gas flow. It is preferred that gas generants for inflators of inflatable restraint devices rapidly generate gases during combustion at desired pressure levels and rates to achieve superior performance and to improve out-of-position performance. Likewise, gas generant materials are preferably safe for handling, have high gas yields and acceptable flame temperatures, with burning rates appropriate to the generant web thickness. Gas generants that fulfill these requirements and further minimize the production of byproduct compounds in effluent gases released through the airbag are highly desirable.